Extraction Behavior of Americium and Plutonium with Mixed Solvent Extractants

Abstract

The mixed solvent extractants, dibutyl N,N-diethylcarba-moylmethylenephosphanate (DBDECMT)-tributyl phosphate (TBP), using carbon tetrachloride diluent, were studied for extracting americium (III) and plutonium (IV) from 0.35 and 7M HNO₃ at 25°C. Synergistic effects were observed in this system as was the case with preliminary results (described herein) using the dihexyl analogue DHDECMP and TBP.     

湿法炼铜常用的铜萃取剂

概述了湿法炼铜中常用的铜萃取剂种类,主要包括：肟类、β-二酮类、三元胺类和复配类等。肟类主要包括酮肟和醛肟,复配类主要讲述了酮肟与醛肟的复配、酮肟复配、肟与β-二酮的复配以及肟与其它化合物的复配。详细介绍了各种萃取剂的性能、结构及用途。同时介绍了国内外研制的几种新型萃取剂的结构及性能。     

纳米二氧化硅表面修饰及其单分子行为研究

用Stber法制备单分散纳米二氧化硅,并以不同链长的脂肪醇对其表面进行疏水改性。研究改性二氧化硅在空气/水界面上单分子层的形成,评价改性二氧化硅的两亲性。由单分子层的π-A等温曲线显示,纳米二氧化硅单分子层结构取决于颗粒表面的疏水性。纳米二氧化硅改性剂的碳链越长,形成的单分子膜的崩溃压越高。     

A Study of the Purification and Acid-Base Behavior of the Commercial Extractants KELEX 100 and LIX 26

Abstract

Several methods for the purification of the active components of the 8-hydroxyquinoline derivative commercial extractants KELEX 100 and LIX 26 have been studies. Among the different methods tried (washing with different solutions, formation of insoluble metal complexes, and column chromatography), the best performance was observed for column chromatography. The active components of KELEX 100 from Ashland (producer up to 1976) and from Sherex (producer from 1976) were characterized using IR, ¹H NMR, ¹³C NMR, and mass spectrometry as 7-(1′-vinyl-3′,3′,5′,5′-tetramethylhexyl)-8-hydroxyquinoline and 7-(1′-methyl-4′-ethyloctyl)-8-hydroxyquinoline, respectively. In the case of LIX 26, a TLC “pure” fraction was isolated and characterized as a 7-alkyl substituted (～ 14 carbon) derivative of 8-hydroxyquinoline that could not be fully resolved. A study of the acid–base properties of the active components of the extractants has also been carried out, and their acidity constants have been calculated by means of both graphical and numerical methods. Finally, several methods for the spectrophotometric determination of these compounds have been proposed.     

二烷基酰亚胺萃取剂的合成与表征

以丙酰氯、正戊酰氯、正庚酰氯为酰化试剂,在温度≤10℃下分别与氨水反应生成丙酰胺、正戊酰胺和正庚酰胺. 以吡啶作缚酸剂,将生成的酰胺与含相同碳链长的酰氯在温度≤0℃下反应,得到3种具有对称结构的含直链烷基的二烷基酰亚胺(二丙酰亚胺、二正戊酰亚胺和二正庚酰亚胺),对终产物进行了表征. 结果表明,以乙醇为良溶剂、水为不良溶剂,经多次重结晶后其最终产率分别为30%, 35%, 33%,终产物的熔点分别为153.7~154.0, 91.5~91.7, 89.0~89.5℃,二烷基酰亚胺纯度大于99%.     

Open-Chain Thioethers as Extractants of Silver

Abstract

Solvent extraction (SX) is a well-established separation technique which has been widely used in extractive metallurgy when it represents a profita-ble alternative (1).     

湿法冶金中的溶剂萃取剂

湿法冶金技术对矿物资源的可持续开发、资源的充分利用和环境保护等方面,发挥了很大的作用,随着湿法冶金技术的不断发展和完善,其在冶金生产中占重要的地位。作为湿法冶金的重要手段的溶剂萃取技术也得到广泛的研究和应用,本文介绍了湿法冶金中的萃取剂的历史发展过程,并将传统萃取剂与双端萃取剂进行对比。     

铜工业萃取剂及其应用

本文详述了国内外用于湿法冶金的铜萃取剂的研制进展，介绍了萃取剂的性能及其在铜的浸出－溶剂萃取－电积法提取工艺中的应用情况；指出浸出－溶剂萃取－电积（Ｌ－ＳＸ－ＥＷ）技术在我国铜工业领域中的前景十分广阔。     

Comparison of Extraction Behavior of Neptunium from Nitric Acid Medium Employing Tri-n-Butyl Phosphate and N,N-dihexyl Octanamide as Extractants

Extraction behavior of neptunium has been compared for tri-n-butyl phosphate (TBP) and N,N-dihexyl octanamide (DHOA) extractants as a function of nitric acid concentration (0.5 ? 6 M HNO₃), uranium loading (50 and 300 g/L relevant to Pu rich fast reactor and Pressurized Heavy Water Reactor, PHWR spent fuels, respectively), and in the presence of oxidizing and reducing agents. These studies suggest the possibility of co-recovery of U(VI), Pu(IV) and Np(IV) from spent fuel dissolver solutions (of Pu rich fuels) employing DHOA as extractant.     

Ionic Liquid Extractants in Molecular Diluents: Extraction Behavior of Plutonium (IV) in 1,3-Diketonate Ionic Liquids

Abstract

Room temperature ionic liquids (RTILs) containing β-diketonate anions have been prepared and studied for the extraction of ²³⁹Pu(IV), ²³³U(VI), and ²⁴¹Am(III) from nitric acid medium. The ionic liquids such as alkylquaternaryammonium thenoyltrifluoroacetonate (R₄NTTA), and 1-alkyl-3-methylimidazolium thenoyltrifluoroacetonate (amimTTA), with methyl, butyl, hexyl, heptyl, and octyl moieties have been prepared and characterized by ¹H and ¹³C nmr and IR spectroscopy. The distribution ratio of plutonium(IV) (D _Pu(IV)) in a solution of tri-n-octylmethylammonium thenoyltrifluoroacetonate (TOMATTA) present in tri-n-octylmethylammonium bis(trifluoromethylsulfonyl)imide (TOMANTf₂) and amimTTA in amimNTf₂ was studied as a function of various parameters. The unique property of β-diketonate ionic liquids, namely, the miscibility in molecular diluents, was exploited to elucidate the mechanism of Pu(IV) extraction in these ionic liquids.     

Phosphazenes as Collective Extractants of Rare-Earth Elements

Theoretical Foundations of Chemical Engineering - The extraction ability of some linear phosphazenes with respect to rare-earth elements (REEs) in a nitrate medium is studied. Some possible...     

基于改进的遗传算法设计萃取精馏萃取剂

将Mod.UNIFAC基团贡献法与改进的遗传算法相结合,进行萃取精馏萃取剂的分子设计。采用了一种简单易行的新编码方案,使合成的分子形式简单,便于链接数据库计算各种性质。提出了跨代精英选择策略,错位交叉算子,滞后变异算子,使设计出的分子结构稳定且形式多样,有效地避免了遗传算法不易得到全局最优解和容易提前收敛的问题。给出了分子设计的主要流程和方法,并编制了相应的计算机程序,将其应用于丙酮-甲醇体系,得到了水和乙二醇等萃取剂。结果表明,文中提出的方法对相对挥发度的预测精度高于文献值,同时检验了该方法的可靠性。     

几种溶媒对林可霉素的萃取工艺特性

研究并比较了林可霉素现有的提取生产工艺和最新研究进展,并对几种溶媒在林可霉素提取过程中影响萃取和反萃取的各种因素进行了深入考察.结果表明,有机酸类萃取体系的综合性能优于中性磷、混合醇、长链醇和丁醇萃取体系,特别是对不同组份的分离效果高于其它几种溶媒.     

Solvent Extraction Studies of Holmium with Acidic Extractants

Abstract

Liquid-liquid extraction studies of holmium with 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester, naphthenic, and Versatic 10 acids have been carried out. The nature of the extracted species and the extraction equilibrium constants of these systems have been determined from aqueous nitrate solution. The extraction mechanism and complexation models have been proposed.     

Solvent Extractive Separation of Zirconium and Hafnium from Hydrochloric Acid Solutions by Organophosphorous Extractants and Their Mixtures with Other Types of Extractants

From 1 to 4 M HCl medium, zirconium was selectively extracted over hafnium by organophosphorous extractants (D2EHPA, PC88A, Cyanex 272). In order to increase the separation factor Zr/Hf, mixtures of organophosphorous extractants with amines (Alamine 336, Aliquat 336) or cationic extractants (Versatic acid 10, LIX 63) were employed in 1–4 M HCl medium. Mixtures with Versatic acid 10 and LIX 63 led to depression in the extraction percentages. But the mixture with LIX 63 was found to be the most effective in separating the two metals among the extractant systems tested in this study. The highest separation factor of around 9.5 was obtained with a mixture of 0.01 M LIX 63 + 0.05 M Cyanex 272 at HCl concentration of 2–4 M. The Zr and Hf were effectively stripped from the loaded mixture of LIX 63 + Cyanex 272 by sulfuric acid solution.     

Polarity of Some Oxime Extractants as determined by gas-liquid-chromatography

The polarity index, retention index, coefficient ϱ and partial Gibbs function of one mole of a solute methylene group and the Sevcik A criterion were determined at different temperatures for some aromatic hydroxyoximes and intermediate ketones by means of gas-liquid chromatography using n-alkanes as nonpolar agents and n-alcohols as polar agents. The relations between these parameters and the relations between the polarity and the compound structure were discussed. In the oxime and ketone molecules the polarity of the hydrophilic groups changes in the following order:  OH>NOH> O ;and  OH> CO> O , respectively. The ketones have less polarity than the oximes. The phenolic hydroxyl group has twice the polarity of the oxime and the carbonyl groups. The chlorine atom at the ortho position in relation to the hydroxyl group sharply increases the polarity.     

Trace-Level Extraction Behavior of Actinide Elements by Aliphatic Alcohol Extractants in Mineral Acids: Insights into the Trace Solution Chemistry of Protactinium

The extraction of actinide elements thorium, protactinium (Pa), uranium, neptunium, and americium by aliphatic alcohols (1-octanol, 2-ethyl-hexanol, and 2,6-dimethyl-4-heptanol) was investigated with solvent extraction and extraction chromatographic techniques from hydrochloric and nitric acid solutions. These systems provide the potential for low-cost, high quality methods for the isolation of Pa from complex matrices. Acid dependency experiments demonstrate the selective extraction of protactinium from hydrochloric and nitric acids, relative to the other actinides explored. Experiments were conducted to elucidate the equilibrium chemical stoichiometry of the protactinium complex that underlies this unique extraction behavior. Slope analysis with respect to the alcohol concentration infers a stoichiometric relationship of 2:1 for the alcohol extractant to the protactinium ion. Slope analysis with respect to the chloride ion (when [H⁺] = 0.1, 1, and 4 M) suggests that the stoichiometric identity of the protactinium chloro-complexes depends on the [H⁺] (0.1 M to 4 M). Extraction of Pa increases as the Pa:Cl ratio increases from 1:2, at low acid concentration, to 1:6 at high acid concentration. With respect to the nitrate ion (when [H⁺] = 1 and 4 M), the stoichiometric relationship was determined to be 2:1 nitrate to protactinium throughout the range investigated. The sum of these findings and observations contribute to a deeper understanding of the unique chemistry of protactinium compared to the other members of the actinide group.     

Synthesis and Utilization of New Extractants for Nuclear Hydrometallurgy

Abstract

Recent progress in organic chemistry increases the possibility of controlling metal ions/organic molecules interaction. The use of macrocycles or polypodands (1) makes possible the creation of specific extractants for each metal ion. According to the actual needs in pollution elimination and precious metal recovery, this approach can lead to important renewals of extractants used in hydrometallurgy. In the present work, selective extraction of plutonium by dicyclohexano-18-crown-6 (DCHI8C6) and paladium by thiapolypodands from high-level nuclear waste solutions is investigated, and the results are modeled and discussed.     

Malonamides as New Extractants for Nuclear Waste Solutions

Abstract

A new class of extractants has been investigated: pentaalkylpropane diamides. Due to their chelating effect on metallic cations, they extract trivalent actinides such as Am³⁺ and Cm³⁺ from acidic nitrate nuclear waste solutions. These solvents are completely incinerable and do not generate large amounts of waste. A review is provided of their chemical properties, leading to the choice of the proper molecule. The results of a bench-scale experiment performed in a mixer-settler battery are presented.     

Diamides as Actinide Extractants for Various Waste Treatments

Abstract

Substituted propanediamides were studied at Fontenay-aux-Roses for the declassification of nuclear liquid wastes by extraction of all the actinides. Their synthesis has been improved. By optimization of the formula, it is possible to use aliphatic diluents without third-phase formation in contact with nitric acid at 20°C. Addition of oxalic acid allows separation of iron and zirconium from americium and plutonium. In selected conditions, it appears that americium extraction is faster than iron extraction, which could lead to practical applications. Recent studies have shown that diamides can be used to remove the actinides from waste solutions in chloride medium coming from defense facilities. The current knowledge and the projects for using diamides as actinide extractants will be reviewed.